1. Field of the Invention
The present invention relates to a method of fabricating a semiconductor device, and more particularly, to a method of depositing a film for a semiconductor device using a single wafer type apparatus employing a lamp heating method.
2. Description of the Related Art
In general, in a chamber in which a semiconductor device fabricating process is performed, a plate known as a susceptor is installed, on which a wafer is placed for processing. The temperature on the surface of the wafer may be controlled by a variety of devices, including a resistance coil, a radio frequency (RF) heating device, an infra red lamp heating device, or a laser.
The infra red lamp heating apparatus has advantages in that the temperature can be increased and decreased rapidly. An example of the single wafer type apparatus employing the lamp heating method is shown in FIG. 1.
FIG. 1 shows a chemical vapor deposition apparatus including a chamber 21 in which an insulation film or a metal film is deposited through the reaction of a source gas and a reaction gas. A shower head 23 is disposed in the upper part of the chamber 21 for introducing the source gas, the reaction gas and an inert gas to the chamber 21. Connected to the chamber 21, through the shower head 23, are a source gas injection tube 1 for supplying the source gas used to deposit the intended film, a reaction gas injection tube 3 for supplying the reaction gas to react with the source gas, and an inert gas injection tube 5 for supplying an inert gas such as helium (He), argon (Ar) or nitrogen (N.sub.2), which does not react with the source gas and the reaction gas. A bypass line 7 allows the source gas to bypass the chamber 21. Valves 11 and 17 control the flow of the source gas through the injection tube 1 and bypass line 7, respectively. Valve 13 controls the flow of the reaction gas through the injection tube 3, and valve 15 controls the flow of the inert gas through the injection tube 5.
A susceptor 25 is disposed in the chamber 21, onto which is mounted a wafer on which a film will be deposited. A lamp unit 27 having a plurality of infrared lamps is disposed below the susceptor 25 and acts as a heating source for heating the susceptor and the wafer. A pressure controller 31 controls the pressure of the chamber 21. The gas is removed from the chamber 21 via a main valve 33 by operation of a pump 35, and is thereafter exhausted through an exhaust tube 37.
Generally, a thin film deposition process using the single wafer type apparatus employing the lamp heating method proceeds as follows. First, the processing conditions of the chamber 21 are stabilized. That is, after mounting a wafer onto the susceptor 25, an inert gas is injected into the chamber 21 via the inert gas injection tube 5, thereby stabilizing the pressure of the chamber 21 at a particular deposition pressure. At this time, the source gas flows through the bypass line 7 while the temperature of the wafer is stabilized at a particular deposition temperature. Next, in order to deposit a thin film, the valve 17 connected to the bypass line 7 is closed, while the valve 11 connected to the source gas injection tube 1 and the valve 13 connected to the reaction gas injection tube 3 are opened, so that the source gas and reaction gas are introduced into the chamber 21 to react and deposit a thin film on the surface of the wafer. Thereafter, the vacuum condition of the chamber 21 is released, and the source gas remaining within the chamber 21 and the source gas injection tube 1 is removed using the pump 35 while supplying the inert gas to purge the chamber 21 and source gas injection tube 1.
More specifically, in the above single wafer type apparatus, wafers are loaded one by one onto the susceptor 25 in the chamber 21. The susceptor 25 is heated directly by the lamp 27, and the temperature thereof is rapidly increased to an intended deposition temperature. Since the temperature of the susceptor 25 is usually maintained at a predetermined temperature close to the intended deposition chamber, the amount of time needed to increase the susceptor 25 to the deposition temperature is very short. However, because the wafer loaded onto the susceptor 25 is introduced to the chamber 21 at room temperature, it takes a long time to increase the temperature of the surface of the wafer and stabilize the processing conditions, thereby decreasing the productivity of the single wafer type apparatus.